Fuse for rotative projectiles



July 25, 1939. E. w. BRANDT 2,167,197

FUSE FOR ROTATIVE PROJECTILES Filed Nov. 2, 1957' w s w r@ r s I0 d) I I 7 v 8 s J I: a) J Patented July 25, 1939 UNITED STATES PATENT OFFICE 2,167,197 FUSE FOR ROTATIVE PROJECTILES Edgar William Brandt,

Paris, France, assignor to Sageb, Socit Anonyme de Gestion et dExploitation de Brevets,

Fribourg, Switzerland, a

corporation of Switzerland 2 Claims. (01. 1o2-s9) This invention relates to a fuse for gyratory projectiles fired in rifled guns and'more particularly to a combined percussion and self-destruc tion fuse of the kind in which arming is efiected by a centrifugal device.

According to the present invention, the action of the centrifugal device which effects the arming of the fuse, is retarded by a pneumatic brake so as to obtain a certain safety distance beyond the muzzle of the gun.

In order that the invention may be more readily understood, reference is made to the accompanying drawing, which illustrates diagrammatically and by way of example, one embodiment thereof and in which:

Fig. 1 is an axial section of the fuse at rest;

Fig. 2 is a similar view of the fuse in the armed condition.

In the embodiment shown, the fuse comprises a body made of two pieces I and 2. The percussion means comprise a striker 3 which is covered by a cap 4.

When at rest, the striker 3 rests with its flange 3a on a row of balls 8 or other locking members disposed in an inclined race la in the fuse body I. from the primer 4a by the locking balls 8. These balls are held in position by an annular member or sleeve 9, which in turn is locked by a split ring Hi located in a groove in said annular member 9 and adapted to'open under the influence of centrifugal force.

The self-destroying system comprises a hammer or hub 5 having housings 5a in which are located balls 6 or other catching members.

These balls 6, which are supported in a groove 9b in the annular member 9 aresubjected to the action of centrifugal force and retain the hammer 5 in counter to the action of a spring I as long as the speed of the projectile remains in excess of a predetermined value. When the speed of rotation of the projectile falls below said predetermined value, said balls 6 release said hammer 5, thus giving rise to the destruction of the projectile before it falls back to earth.

The annular member 9, is locked by a split ring l0 lodged in a channel or groove 9c of the annular member 9, said split ring engaging a shoulder 9d of the fuse body.

' The front portion of the fuse-is closed by a thin plate H.

The device operates as follows:

When the shot is fired the annular member a which is held by inertia at the rear end of The striker 3 is thus held away the fuse, prevents any displacement of the locking members 8. However, when acceleration of the projectile has ceased, that is to say, after leaving the cannon, the fuse can be armed.

At firing, the ring l0, displaced from its groove 90 by the centrifugal force, liberates the annular member 9. This latter, thrust by the balls 8 which tend to diverge more and more by sliding on the oblique surface 9a, is raised and carries with it the hammer 5 of self-destruction device which is in turn held by the balls 6 engaged in the groove 9b, compressing the spring 1.

When the balls 8 have reached the position shown in Fig. 2, the fuse is armed. The striker 3 is then liberated and the self-destruction device is ready to work. g The arming however is not effected instantaneously, as would be the case if the annular member 9 could be displaced very freely in the nose of the fuse. On the contrary, the movement of arming is braked by a pneumatic effect obtained by virtue of the annular member 9 acting as a piston by compressing the' air in the chamber I2 formed by the upper face of the ring and the corresponding part of the fuse nose. The compressed fluid can escape only through the relatively small space between the sliding surfaces, so that the annular member 9 takes a certain time to reach its arming position. This time corresponds to a certain safety distance for the fuse.

Instead of being fixed in the fuse body as shown in the drawing, the primer to could be mounted, in a known manner, in a movable primer carrier.

It is obvious that the positions of the two firing members (striker 3 and primer la) may be reversed without in any way affecting the herein described operative principle. In such a case the primer should of course be mounted in a primer carrier.

I claim:

1. A combined percussion and self-destruction fuse for projectiles fired in rifled guns, comprising a fuse body, firing members in said fuse body and including a striker and a primer, said firing members being adapted to be urged against each other through direct action of an obstacle encountered by the projectile on its trajectory, locking members interposed between said firing members, a sleeve surrounding said locking members for maintaing the same in locking position, a hammer adapted to slide in the fuse 'body for engaging one of said firing members whereby to thrust the firing member against the other of said firing members to produce selfdestruction of the projectile, said hammer being provided with laterally extending holes, centrifugal catching members lodged in said holes and adapted to slide therein, a spring urging said hammer into engagement with the firing member with which it cooperates, said sleeve being provided with a groove with which said centrifugal catching members are adapted to engage under the effect of centrifugal force caused by the gyratory motion of the projectile, said centrifugal catching members being adapted to remain engaged with the holes in said hammer and also with the groove in said sleeve during a given part of the trajectory while the rotative speed of the projectile is greater than a predetermined value and said catching members being subsequently moved away from said groove by said spring when the speed falls below the predetermined value under the braking action of the fluid through which the projectile travels whereby the hammer is freed and pushed by the spring into engagement with one of the firing members whereby to thrust it against the other of said firing members, said sleeve being formed with faces adapted to be engaged by said locking members and to cooperate therewith to effect sliding movement of the sleeve under the action of the centrifugal force of said locking members, said fuse body having an internal surface corresponding in shape to the external surface of said sleeve, and said sleeve being adapted, when in armed position, to engage throughout its entire external surface with the corresponding internal surface of said fuse body whereby to obtain a pneumatic braking effect by the sliding movement of the sleeve delaying the arming of the fuse until after the projectile has travelled a certain distance beyond the muzzle of the gun.

2. A combined percussion and self-destruction fuse, as claimed in claim 1, wherein the sleeve is provided with an external circular channel and the fuse body is provided with a shoulder in the region ofsaid channel, and wherein a yieldable split ring is disposed in said'channel and is adapted to cooperate with said shoulder to lock the sleeve in a position of rest, said split ring being adapted to escape from the locking position by inertia at firing whereby to unlock said sleeve.

, EDGAR WILIJAM BRANUI. 

